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<h1>Thallium arsenic selenide, Tl<sub>3</sub>AsSe<sub>3</sub> (TAS)</h1>

Thallium arsenic selenide (Tl<sub>3</sub>AsSe<sub>3</sub>, often referred to as TAS) is a mixed crystal compound known for its nonlinear optical properties and high electro-optic coefficients. Its large transparency range, spanning the mid-infrared spectrum, makes it a valuable material for infrared detectors, parametric oscillators, and other optoelectronic devices. TAS is especially useful in applications that require fast response times due to its high-speed electro-optic effect. However, handling and processing TAS should be approached with caution, as both thallium and arsenic are highly toxic.
